Fuel injection apparatus for internal combustion engines



April 1, 1941. w. VOI.T Ema.

FUEL INJECTIOK APPARATUS FOR INTERNAL COMBUSTION ENGINES 2 Sheets-Sheet'1 Filed Dec. 16, 1936 W. VOIT EI'AL April 1, 1941 FUEL INJECTIONAPPARATUS FOR INTERNAL COMBUSTION ENGINES Filed Dec. 16, 1936 2Sheets-Sheet 2 tinder the influence of a spring Patented Apr. 1, 1941FUEL INJECTION APPARATUS FOR IN TERNAL COMBUSTION ENGINES Willy Voit,.Stuttgart-Bad Cannstatt, and Johannes Weber, Stuttgart -Feuerbach,Germany, assignors to Robert Bosch Gesellschaft mit beschriinkterHaftung, Stuttgart, Germany Application December 16, 1936, Serial No.116,226 In Germany December 23, 19.35

9 Claims.

This invention relates to fuel injection apparatus for internalcombustion engines, comprising a fuel injection pump, control means insaid and the other with the induction pipe of the engine. The twochambers are separated from one another by a movable governor member, e.g. 9; piston or a membrane, and said member is means which tends to movesaid member in the direction ofincreasing fuel delivery wherea thenegative pressure or vacuum in the inducton pipe causes the member tomove, in opp sition to said pump for adjusting the fuel delivery of thepump, I

spring means, in the direction of'decreasing fuel delivery.

" When employing this kind, the different loads on the engine areadjusted for by a movable throttle which is arranged in the inductionpipe of the engine.

By closingorpartially closing the, throttle, the

airflow in the pipe can. be restricted so that the vacuum in thegovernor chamber connected therewith increases. With the increase ofthis vacuum the movable governor member is moved in such a way as todecrease the fuel delivery. In this case the movement of the governormember takes place in opposition to the spring means. By fully openingthe throttle the vacuum will decrease and adjust the control means sothat the injection pump delivers large amounts of fuel and the engineruns with full power.

J With the throttle in its open or full power 3 position; many differentengine speeds occur, especially in vehicle engines, and it depends onfuel injection apparatus of the maximum engine speed has'been' exceeded.

This type of governor can also be used for ad justing the fuel supply atloads less than full engine load byclosing the throttle sufficiently todecrease the supply of fuel accordingly.

In internal combustion engines in which full load'occurs over a greatrange of speeds, as principally in vehicle engines, it is important totake steps to enable the greatest possible torque to be obtained fromthe engine at any speed. A very important preliminary'condition for thisis that, at each speed, the maximum amount of fuel which the engine canburn'without producing smoke, should be supplied to it. This amountvaries with the speed in most types of engines. It may increase as thespeed increases, in some cases however it remains the same over thewhole range of speeds but usually the amount of fuel for running under'full load that can be burnt withoutsmoke will decrease as the speedrises.

. For any engine the maximum amount of fuel that can be consumed withoutsmoke when running under full load can be experimentally determinedforeach speed. If the ascertained values are inserted in a system ofco-ordinates, a curve is obtained, which may be termed the consumptioncurve. According to whether this curve rises, remains the -same, orfalls, as

the engine load whether the engine speed is high or low. A high loadreduces and conversely a small load increases the engine speed.

It is well known to those skilled in the art theta pneumatic governor ofthe type described Y can be used to avoid an undesired increase of theengine speed beyond an admissible maximum. When the engine has exceededthe maximum speed at which it gives its full output, the vacuum in thegovernor chamber connected with the induction pipe will increase tosuch,a degree that it displaces the movable governor member, against theopposing spring means, and with it the control means, into its nodelivery position, thus fully cutting off the fuel delivery to theengine. With the throttle in its fully open position, the fuel supplycan be cut off only when the speed increases, the engine can be spokenof as having a .rising, uniform or falling consumption curve.

The course of the. consumption curve of an engine depends on variouscircumstances. The falling consumption curve will be frequently metwith,.more especially in the case of engines hav ing a high maximumspeed, because the air .charge in the engine cylinders decreasesconsiderably for known reasons in the higher speed range, so that themaximum amount of fuel which can be consumed without producing smokealso correspondingly decreases.

In injection internal combustion engines, the

injection pump measures the amount offuel.

Every injection pump has a definite delivery amount curve which isproduced on a definite, unvarying adjustment of the delivery amountadjusting member depending on the different speeds. Pumps having inletscontrolled by sliding valves have for example a delivery curve thatrises withthe speed; Other pumps, for instance those having the usualsuction valve, have a delivery-curve which remains fairly uniform overthe range of speeds that occur.

If now it is desired to introduce the maximum amount of fuel consumablewithout smoke into an injection engine in the whole speed range, inorder to enable the highest possible torque to be obtained from theengine at all speeds, attention must be given primarily to making thedelivery curve of the injection pump apparatus assimilate or conform asfar as possible to the course of the consumption curve of the engine.The best conditions result, of course, when the two curves coincide.

This invention provides a new way in which in a simple manner, in spiteof the comparatively great pressure or high pretension and smallstiffness of the return spring necessary for cutting off of the fuelsupply when maximum speed is exceeded in injection apparatus havingpneumatic governing, the amount of fuel delivered to the engine can beregulated in such a way that the delivery curve of the injectionapparatus can be adapted or coordinated to the consumption curve ofengines having a strongly falling consumption curve so that at eachspeed at full load the engine operates with maximum power and withsmokeless combustion.

According to the present invention, in a fuel injection apparatus forinternal combustion engines comprising an injection pump having a fullloaddelivery curve which rises relatively to the consumption curve ofthe engine as the speed increases, and a pneumatic governor whichcontrols the fuel amount delivered by the injection pump to the nozzlesand adjusts the delivery amount controlling member of the injection pumpin dependence on a return force and on a pneumatic drop in pressureacting in opposition to said return force, which drop in pressure varieswith the engine speed as well as with the position of a voluntarilyoperable throttle, a novel return force is provided wh eby under fullload conditions, that is to say, i' a range between full load at lowspeed and full load at maximum speed, the effective resultant value ofthe said return force is such that the difference in depressionoccurring within this full load range due to differences in speed of theengine can cause by a corresponding displacement of the control member,an assimilation of the fuel delivery curve of the pump to thatconsumption curve of the engine which gives smokeless combustion at eachspeed at full load to enable the engine to operate at maximumefiiciency, said return force also coacting, however, with the pposingdepression or increase, to regulate the fuel amounts when maximum speedis exceeded and at all speeds less than maximum under partial load.

The return force acting on the governor meniber of the pneumaticgovernor comprises a 2- stage spring means, one stage of which has ahigh pretension corresponding to the vacuum existing at maximum speed inthe governor chamber but of such weakness that it is overcome by afurther increase of vacuum when the maximum speed is exceeded, the otherstage of said spring means having a low pretension, if any,corresponding to the slight vacuum existing below maximum speed withwide open throttle, but of such a strength that below maximum speed andwith wide open throttle it adjusts the control means to the slightvacuum and small variations of vacuum in the induction pipe of theengine so that the control means causes the pump to deliver themaximumquantity of fuel which can be burned smokelessly.

Various examples of construction of the invention are shown in theaccompanying drawings in which: V

Figure 1 shows, partly in longitudinal section a fuel injection pumpprovided with a vacuum or pneumatic governor embodying this invention.Figure 2 is a diagram of the curve of the spring forces of the injectionpump governor.

Figure 3 is a diagram of the delivery curve 01 the pump and theconsumption curve of the engine.

Figures 4, 7, 10 and 13 are enlarged sections of different examples ofconstruction of spring stops for the delivery amount adjusting member ofthe pump, while the curves of the spring forces and the maximum deliveryamount of the pump appertaining to each example are indicated in thediagrams (Figs. 5, 6, 8, 9, 11, 12, 14, 15) adjoining said figures.

- l indicates the injection pump, the cam-shaft 2 of which drives thepistons 3 of several separate pumps. On this injection pump a pneumaticgovernor 4 is built, in which a diaphragm 5 moves a toothed controllingrod 8 of the injectionpump. By the movement of the controlling rod allthe pump pistons are uniformly angularly turned or r0tated,'whereby anoblique helix controlling edge arranged on the end of each piston isadjusted in relation to a return flow opening, so that a variable amountof the fuel forced by the pistons can flow back. An externally closedgovernor chamber 1 of the pneumatic governor 4 is connected by a pipe 9to the induction pipe 8 of the engine, the other governor chamber llbeing open to the atmosphere. A throttle member ID is rotatably mountedin the induction pipe 8 of the engine and by closing or partiallyclosing the throttle ID, a vacuum is producedin the chamber 1. Thevacuum will displace the diaphragm 5 and this in turn displaces thecontrol rod 6 in the direction which decreases the amount of fuelinjected. The opposite movement of the control rod 6 takes place whenthe vacuum in the chamber I decreases, e. g. by adjusting the throttleinto the open position as seen in Fig. 1. With the throttle in its openposition, a smaller vacuum arises than when it is in its closed orpartially closed position. The. opening and closing movement of thethrottle and the speed of the engine are made use of to adjust bothlarge or small injection amounts at full or part engine loads. Thethrottle in the present case is used primarily to control the vacuum inthe governor chamber and for this reason it is only necessary topartially close the throttle to obtain sufllcient vacuum to adjust thefuel delivery for part load and idling speeds. Within the chamber '1,there is arranged a spring I! which presses the diaphragm 5 and thecontrol rod 6 towards the left hand side in Fig. 1. The force of thereturn spring l2 tends to adjust the diaphragm and the controlling rodin the direction which increases the amount of fuel injected.

An injection pump of the type shown has per se a rising delivery curveaccording to the line A and the curve of the maximum fuel amountconsumable by the engine, without producing smoke, may have a courseindicated by the broken line C in Fig. 3. In order to assimilate thedelivery curve of the injection pump fitted with a pneumatic governor tothis consumption curve, which falls as the speed increases, an opposingspring I3 is so arranged on the left hand end of the pump casing I asshown in Fig. 1, that it bears with one of its ends against anadjustable bottom or stop member I in a sleeve I4, while the other endof the spring I3 bears on a movable stop IG for the left end of thecontrolling rod 6. The springs I2 and I3 prevent the pump fromdelivering amounts of fuel over and above those shown by curve C,provided the throttle is fully open.

When the engine is not running there is no vacuum either in theinduction pipe 8 or in the governor chalinber I. The springs I2 and I3are now the only forces which have influence on the control rod "'8 andkeep it in a certain position of equilibrium.

When the engine is in operation, a vacuum will arise in both theinduction pipe 8 and the chamber I, which vacuum will have the tendencyto draw the diaphragm 5 towards the right for decreasing the fueldelivery amount, which movement is opposed by the resultant force of thesprings.

The left end of the controlling rod stands, when the engine is stoppedor not running, in the position Ia, as in this case no drop in pressureacts on the diaphragm, so that the pressure of the return spring I2 andthat of the opposing spring I3 are equal. If now the engine is runningunder full load (i. e. the throttle valve fully open) at a slow speed,for example when the car is traveling uphill, the left end of thecontrolling rod is in the position denoted by I.

At a high full load speed the current in the air induction pipe isstronger, so that the vacuum in the governor chamber increases somewhatand pulls the diaphragm more to the right, until the left end of thecontrolling rod in the region of maximum speed reaches the position II.In this position of the governor parts the force exerted by the opposingspring I3 on the controlling rod has been expended, and upon a furtherincrease in speed and in vacuum, the control rod is moved further to theright so that the left end of the controlling rod comes out of the rangeof action of the opposing spring. In position III of the end of thecontrolling rod, only the amount of fuel necessary to maintaining idlerunning is still delivered. The controlling rod moves into this positionIII when the throttle valve is fully open when maximum speed isexceeded. With the throttle valve partially closed (idle runningadjustment), the vacuum then existing in the induction pipe 8 and in thegovernor chamber 1 is also able to pull the controlling rod intoposition III. The stop position of the controlling rod is indicated atIV.

The spring I2 has the characteristic indicated by I2 in Fig. 2, adiagram in which the ordinates show the force exerted by the springs andthe abscissas the stroke of the movable end of each of the springs. Thepositions of the left end of the controlling'rod in Fig. 1 correspond tothe spring path IaIV in Fig, 2. The spring I3 has the characteristicindicated by numeral I3 in Fig. 2 and shown by a dotted line below theaxis of abscissas to illustrate that spring I3 works in the oppositedirection to spring I2. In position Ia both springs have the sametension in opposite directions and are in equilibrium. From Ia to II thetension of spring I3 decreases until at II the spring I3 has fullyexpanded. Between Ia and II the springs l2 and I3 work together like aspring with the resultant characteristic X in Fig. 2 and as if such aresultant spring were opposed I to the vacuum in the chamber 1.

chamber 1 increases with increasing engine speed because with increasein speed the velocity of the air-flow also increases. With the throttlein its open position the vacuum in the pipe 9 leading into the inductionpipe and in the chamber I is relatively small as long as the engine isrunning at slow speed under full engine load because the velocity of theair-flow in the induction pipe is also small. The vacuum increases withincreasing engine speed and becomes at the maximum speed so great thatit overcomes the relatively high pretension of spring I2.

Fig. 1 shows the control rod 6 with its left end in the position I, butit will stand in the position Ia when the engine is stationary and thepressure is the same on both sides of the diaphragm 5. From the Iaposition in which equilibrium exists between the springs I2 and I 3, thecontrol rod moves towards the right as soon as the vacuum in chamber 1overcomes the resultant spring force X. In order to achieve this a smallvacuum will be sufiicient as the strength of X near Ia in Fig. 2 issmall. In fact, even the small vacuum will suifice which occurs inchamber 1 when, with the throttle in the open position and with highengine load (e. g. driving uphill) the engine speed has very muchdecreased, for instance down to the lowest speed at which the engine isstill able to operate under full load. In the following, this lowestspeed will be referred to as lowest full load speed. The position of thecontrol rod 6 corresponding to the lowest full speed is that indicatedby I in Fig. 1. Now, if with decreasing torque the engine speed and thevacuum increaseswhile the throttle remains in its open position-theincreasing vacuum will further shift the control rod Ii towards theright against the resistance of the spring the strength of whichincreases corresponding to the rising course of X. Between I and II inFigs. 1 and 2 the shifting movement of the control rod 6 will terminatein those positions in which the vacuum and the strength of the resultantX are in equilibrium. The springs l2 and I3 are so dimensioned and theresultant X so chosen that with increasing speed-the throttle, be itremembered, always being open-the left hand end of the control rod 6 hasreached the position II at the maximum en-.

gine speed. That is the highest possible engine speed which isadmissible for the engine under full load. In this position II thespring I3 has fully expanded and the stop I6 touches only lightly theleft hand end of the control rod 6. If because of further decreasingengine torque (for instance when driving downhill) the engine speedexceeds the maximum speed, the vacuum would further increase; but as theexpanded spring [3 no longer operates at the right hand side of II-inwhich position only spring I2 Works-at II another range of governingwill begin. Here, only the spring I2 will resist the increasing vacuum.As according to Fig. 2 the stiffness of the spring I2 is very small,only a small increase of vacuum, corresponding to a small increase ofspeed over maximum speed, is necessary to shift the control rod 6towards IV and so fully cut-of the fuel delivery at a speed which is notvery much higher than maximum speed. Thus by exceeding the maximum speedonly slightly the fuel delivery is fully cut-off, while below maximumspeed the stiffer characteristic X will cause an even alteration in theamount of fuel delivered in dependence on variations of engine speed asFig. 3 is intended to show.

It will be seen from this diagram that the coaction of the spring I2 andI3 only takes place between stop position (Ia) and the maximum speed atfull load position (II). When the speed exceeds the predeterminedmaximum speed at full load the final regulation or cutting off of thefuel supply starts, and the return spring I2 is increasingly compressedby the increasing vacuum until the idling amount adjustment (III) andfinally the stop position (IV) of the controlling rod is reached.

In Fig. 3 the maximum speed is indicated by m and the lowest full loadspeed by m. It has already been mentioned that between these two limitsof speeds one stage X of the spring means comes into operation, i. e.the stage in which both springs I2 and I3 operate, while above 11.2 inthe other stage only spring I2 is opposed by the vacuum.

According to the present invention the strength of the resultant springmeans X is such that the delivery curve A of the pump is assimilated asd which is practically the same as that of the commonly known maximumspeed regulator cuttingoff fuel supply at maximum speed.

It will be seen, therefore, that according to this invention, thecontrol of the fuel amount takes place in the full load speed range bythe coaction of the forces in a different way than if only the fall inpressure and the main return spring I2 were operative.

Fig. 4 relates to another embodiment of the invention. If differs fromFig. l by the fact, that the stop I6 has a prolongation I! which extendsthrough the bottom of the sleeve Ma and can at will be drawn manuallyfurther to the left, beyond the position Ia in which it would stand whenthe engine is not running, into a position ID in which the stop I6 bearson the bottom of the sleeve. When the engine is out of operation and thestop I6 has been drawn manually to the left, the control rod will followthe stop under the pressure of spring I2 until the end of the controlrod 6 has reached the ID position. In this condition, the injection pumpis so adjusted that the pump delivers an excess amount of fuel which inmany cases is desirable for starting the engine.

During the excess fuel adjustment period the left, excess fuel amountscan be adjusted which according to the left hand part of curve C between11.. and m in Fig. 6 are shown to be larger than the full load deliveryamounts between m and n2, adjusted by the springs I2, I3 after the stophas been released so that the springs can cperate in the mannerdescribed in Fig. 1.

In Figure 5, as in Figure 2, the strength of the springs I2 and I3 areplotted as ordinates over the length of spring travel, the positions ofthe left hand end of the control rod in Fig. 4 corresponding to thespring travel 11) to IV of Fig. 5. The combined action of the springs I2and I3 is shown by the line X (Fig. 5) disposed between the position 111and the maximum speed position m Fig. 6). The left hand end of thecontrol rod moves in this speed range from the position Ia to theposition II (Fig. 5).

If prior to starting the engine, the driver manually displaces theexcess fuel stop IE to the left,-

then the tension of the spring I3 is overcome by him in the position Iaof the control rod so that spring I3 no longer acts in opposition to thespring I2, which latter spring is then free to expand so that thecontrol rod moves until its left hand end comes into position Ib inwhich this control rod, when the engine throttle is wide open and theengine is revolving at low speed sets the pump to give an increasedquantity of fuel, which is often desirable at starting of the engine.This condition is shown in Fig. 6 in which the quantity of fuel injectedper stroke is plotted against revolutions per minute.

Should the excess fuel device he pulled back, the fuel delivery curvewould rise throughout the range, above the curve A and parallel theretobut as the governor comes into operation at or about the point 121 thiscurve will take the form shown at C-where only the first part of thecurve lies above the curve A but the latter part of the curve fallsbelow it.

Further according to this invention, the strength of the opposing springcan be adjusted. An example of such an arrangement is shown in Fig. '7.One end of the opposing spring I3 bears on the adjustable bottom or stopI5 of the sleeve Ma, and the other end bears on the movable con-.trolling rod stop I6. At a low full load speed (position It.) the stopI6 impinges on the bottom I5 of the sleeve Ida, while the spring I3 iscompressed. As the stop I6 impinges on the bottom I5 before the left endof the controlling rod has reached a position Id equivalent to theposition Ia, of the above examples, in which it would stand onnonrunning of the engine, if the stop was not present, a condition ofequilibrium of the springs I2 and I3 cannot occur as in the arrangementsshown in Figs. 1 and 4. The adjust-able bottom is moved, furthermore,according to Fig. 7 beyond the non-running position Id (Ia as indicatedin Figs. 1 to 4) somewhat further to the-right into osition Ic, so thatthe end of the controlling rod approaches still nearer the position 11that corresponds to the maximum speed at full load. In this initialposition the pressure of the return spring preponderates over theopposing spring in the region of low full load speeds (Fig. 8) so thatthereby the controlling rod is pressed against the stop. With thethrottle valve fully open and low full load speeds, no assimilatoryaction of the opposing spring takes place, because the controlling roddoes not move, and the delivery amount of the pump increases as shown bythe line A (Fig. 9). It is only when a higher full load speed is reached(as indicated at point no Fig. 9) that the drop in pressure can overcomethe pressure of the return spring against the stop, and then thecpposing spring can act to cause assimilation by reducing the deliveryamount of the pump. The resultant of the two spring forces increasesowing to the increase in the drop in pneumatic pressure as shown in Fig.8 only from a definite speed us which corresponds to the stop-position10 of the left end or the controlling rod, until the maximum speei atfull load n: is attained, when the cutting off of the fuel feed begins.The delivery amount of the pump, increasing at first with the curve A,is this assimilated to the consumption curve of the engine, as shown inFig. 9, from the full load speed 12.: onward according to the curve C.

If now the bottom I5 of the sleeve I5 is moved to the left, the returnspring can displace the left end of the controlling rod into theposition Id against the opposing spring, while the return spring furtherexpands. Accordingly at first, a.

123.1NTERNAL COMBUSTION ENGINES.

pended and cannot operate any longer.

somewhat larger injection amount is adjusted. As the speed increases,however, the vacuum can now put the diaphragm and controlling rodsomewhat earlier into movement and pull them to the right, during whichthe opposing spring acts in an assimilatory manner. The opposing springwill now also be earlier expanded (IId), as its abutment (bottom l) hasalso been displaced. Its assimilatory action thus ceases even before themaximum speed at full load is reached. The curve C' will thus at firstlie above the line A and parallel thereto, then fall, and finally againrise somewhat up to the full load maximum speed. The assimilation canthus be limited, according to the invention, to a portion of the fullload speed region.

Figs. 3 and 6, previously discussed, are based on the fact that theengine would have a fuel consumption curve C, C' respectively with a.falling tendency for the whole full load speed range between 11.1 and11.2. In Fig. 9, the consumption curve C" is that of a combustion enginewhich can combust without smoke increasing fuel amounts up to us, (thiscurve coincides from n. to 11 with the delivery curve A of the pump),but from m to n: the consumption curve C" falls. In this case, analteration of the fuel delivery of the injection pump below no is notnecessary, but only above m. In order to obtain an alteration between ncand n: the bottom l5 of the sleeve Ila is to be adjusted as previouslydescribed so that the stop l6 does not permit movements of the controlrod to the left beyond IO. The control rod 6 will then remain in thisposition as long as the speeds remain below us, the throttle being inthe open position. Thus, below m the injection pump delivers accordingto its delivery characteristic A, while from m up to 122 the resultantstrength X (see Fig. 8) of the springs I2, I 3 is in operation and fromn: to m'the strength of spring I! alone.

In the case where the engine has a consumption characteristic shown bythe dash and dotted line C' in Fig. 9 with deviations at nd and mm, withthe same means as shown by Fig. 7, it will be possible to influence theinjection pump according to curve C'. In order to achieve this result itis only necessary to slacken the bottom I!) of the sleeve Ha so far thatthe control rod 6 would be stopped at Id, while in the first-mentionedadjustment the lefthand movement of the control rod was limited at 10.In the same manner as during the previous adjustment Ic the injectionpump delivered below us. according to its delivery curve A-because thecontrol rod does not move below no with the open throttle-the smallvacuum below nsin the open position of the throttle-will not move thecontrol rod. Therefore, below 114 the injection pump will deliver withthe control rod in position Id (which corresponds to a larger fueldelivery amount) according to a deliver curve the course of which issimilar to the curv A but higher because the position Id of the controlrod corresponds to a larger delivery amount than 10. Above na the vacuumincreases and the resultant force X in Fig. 8 determines the deliveryamounts. While with the stop in the Ic position the control rod will beadjusted by the resultant force X between m and m from In to II; theadjustment of the stop l6 into position Is will cause X to operatebetween Ia and IId when the speed increases from na to mm, a speed lowerthan m. From the said speed ndz onwards the spring 13 has fully :11:-

Search Room the spring l2 will still remain in operation. But thestrength of spring I 2 at IIa (Fig. 8) is not much different from thestrength at II and can, therefore, not be contracted by a vacuum whichis not essentially smaller than that at m. For this reason, the controlrod 6 keeps its position IId until the speed 12.: has been approximatelyreached. In position 11d of the control rod the pump will deliveraccording to a curve which is parallel to A (between nan and m) Above112 the vacuum in the induction pipe will contract spring l2 and cut-offthe fuel delivery in order to prevent the maximum speed 112 beingexceeded.

Fig. 10 represents another example of construction, in which the lefthand end of the stop I 6 is adjustable by a screw 18, but the bottom ofsleeve Ma, which forms an abutment for one end of the spring 13, isimmovable. While the screw I5 in Fig. 7 was the abutment for both thestop 16 and the spring I3 and so shifted when displaced the wholeoperating range of X in Fig. 8, in the present case only the left handrange of the operation of the control rod 6 is adjustable and the rangewhich operates when the control rod 6 and the stop l6 are out of contactwith one another cannot be altered. This will be seen from the followingexplanation.

By adjusting the screw I8 in such a manner that the right hand end ofthe stop l6 and the left hand end of the control rod 6 are in positionI: (see Figs. 10 and 11), the resultant force X of the springs l2, l3can only be operable between 11: and n: (Fig. 12). Below n: theinjection pump will operate, without the position of the control rod 6being altered, according to the curve C which has the same course as thedelivery curve A of the pump. Above 11.: the pump will deliver fuelamounts according to the dotted line in Fig. 12 between m and m. If by adifferent adjustment of screw l8 the control rod is permitted to reachposition Ie, the control rod can follow the stop I6 until at m (beyond11:) a higher fuel delivery amount is obtained. From I: to I. a furtherdecrease of X occurs as can be seen from the dotted part of the line Xin Fig. 11. At the same time the fuel delivery amount increases between12: and m as can be seen from curve C" in Fig. 12 which rises from m tom while below us the fuel delivery curve C" is parallel to the injectionpump delivery curve A as the vacuum in the open position of the throttleat the low engine speeds below m cannot displace the control rod.According to this arrangement, it is possible to adapt the deliverycurve of the pump to the consumption curve of the engine to the fullestpossible extent.

Fig. 13 shows another embodiment of the invention and Figs. 14 and 15are diagrams for illustrating the operation thereof. 1 is the governorchamber, which is formed by the governor casing 4a and the membrane 5.It is connected by the pipe 9 with the induction pipe of the engine.Within the casing there is arranged a spring II, which at one end restsupon the bottom of the casing la and at the other end presses a disc I!against astop ring 22 fixed to the cas ing. Stop ring 22 limits movementto the left of disc 19, movement thereof to the right being limited bystop 23. Under the pressure of the spring l2, the disc 19 forms asupport for one end of a second spring 2| which at its other end bearson the diaphragm 5. In the position shown in the drawings, the spring I!cannot direct its whole pretension on the membrane, but only with thesmaller tension of the spring H. The characteristics of the springs l2and 2| can be seen from Fig. 14. As the pretension of spring 2| is verysmall compared with the pretension with which the spring I2 is pressedagainst the disc l9, the spring 2| alone will be contracted as long assmall vacuums arise in chamber 1. In this case the parts 5, 2| and 6will move without contracting the spring l2. During such movements ofthe control rod 6 under the small vacuum at open throttle below maximumspeed 122, the delivery amounts of the pump-according to curve A in Fig.l5-will be reduced to amounts C in Fig. 15 which can be burned in theengine cylinders Without smoke.

The spring 2| has been dimensioned so that by the small vacuum atmaximum speed 112 it will be contracted so far that the membrane 5 abutsagainst a tubular part 20 connected with the disc Ill. The membrane willabut against the tubular member at II in Figs. 13 and 14. When thevacuum further increases upon an increase of speed above maximum speedm, the membrane 5 will be drawn so much towards the right that now thepretension of spring I2 will be overcome, taking with it the control rod6 and cutting-off the fuel delivery. From the foregoing it will be seenthat, as in the previous examples, the example of construction accordingto Figs. 13, 14, 15 also has two stages of operation, one low vacuumstage in which a relatively stiff spring 2| of small pretension isopposed to the small vacuum occurring at open throttle below maximumspeed and adjusts the fuel delivery of the pump in such a manner thatthe engine produces at each full load speed the maximum possible powerwithout smoke, and another high vacuum stage in which a spring l2 ofhigh pretension but of relatively weak chaacteristic (small alterationof strength in the large stroke between II to III) is operable tocut-off the fuel delivery above maximum speed.

We declare that what we claim is:

1. In an internal combustion engine of the injection type having an airintake manifold and a throttle valve therein, the combination comprisingadjustable fuel injection means, a displaceable control member connectedto said fuel injection means for controlling the quantity of fuelsupplied to said engine, means housing said control member and definingwith the two sides thereof two chambers, one on each side of said tionsin the intake manifold will function to displace said control member bydifferential pressure acting thereon in opposition to said resilientforce to adjust the fuel injection means, and resilient means operativeonly when said control member reaches a position for adjustment of fuelsupply within the full load range of said engine and at speeds belowmaximum and then automatically Operating o p y a r istin force to saidcontrol member in opposition'to the force appliedbisaid first-mentionedforce-applying means, the resultant force exerted on said control memberby said opposed force-applying means being so weak that said controlmember is sensitive to and movable by the small pressure differenceswhich occur in said chambers when the engine runs with wide openthrottle under full load at speeds lower than maximum speed.

2. In an internal combustion engine of the liquid fuel injection typehaving an air intake pipe and a throttle valve therein manually operableat will, a fuel supply system and control means therefor adapted tocontrol the speed of the engine, said fuel supply system and controlmeans therefor comprising a fuel injection pump driven by said engine, adisplaceable fuel quantity control member, means mounting said controlmember for movement in opposite directions, said control member beingmovable in one of said directions by difference in fluid pressures onits opposite faces, means exposing one face of said control member toatmosphere and its opposite face to the pressure in said intake pipe onthe engine side of said throttle valve, means operated by said controlmember to reduce the fuel delivery of said pump in accordance with thedisplacement of said control member in said one direction, resilientmeans operable to apply a resisting force to said control member inopposition to the efiect of said difierential pressure, and auxiliaryresilient means inoperative until said control member reaches a positionfor adjustment of the fuel delivery of said pump within the full loadrange of said engine at speeds below maximum and with wide open throttleand then automatically operating to apply a resisting force toyieldingly resist movement of said control member in the fuel-increasingdirection, the resultant force exerted on said control member by the tworesilient means being so weak that said control member is sensitive toand movable by the small fluid pressure differences to which saidcontrol member is subjected when the engine runs with wide open throttleunder full load at speeds lower than maximum speed.

3. Apparatus as set out in claim 2 including means for adjusting thetension of said auxiliary resilient means.

4. In an internal combustion engine of the liquid fuel injection typehaving an air intake pipe and a throttle valve therein manually operableat will, a fuel supply system and control means therefor adapted tocontrol the speed of the engine, said fuel supply system and controlmeans therefor comprising a fuel injection pump driven by said engine, adisplaceable control member, means mounting said control member formovement in opposite directions, said control member being movable inone of said directions by difference in fluid pressures on its oppositefaces, means exposing one face of said control member to atmosphere andits opposite face to the pressure in said intake pipe on the engine sideof said throttle valve, means operated by said control member to reducethe fuel delivery of said pump in accordance with the displacement ofsaid control member in said one direction, resilient means operable toapply a resisting force to said control member in opposition to theeflfect of said differential pressure, and a resilient device located inthe path of movement of said control member so as to engage said controlmember as it reaches a position for fuel delivery control for full loadrunning of the engine at speeds below maximum and thereby to yieldinglyresist movement of said control member in the fuelincreasing direction,the resultant force exerted on said control member by said resilientmeans and said resilient device being so weak that said control memberis sensitive to and movable by the small f'luid pressuredifl'erencestowhich said control member is subjected when the engineruns with wide open throttle under full load at speeds lower thanmaximum speed.

5. Apparatus as set out in claim 4 including manual means fortemporarily rendering said resilient device inoperative during startingof the engine. l

6. Apparatus as set out in claim 4 including means for varying the endposition of said resilient device in the direction of increasing thefuel amount.

7. A fuel supply system for internal combustion engines provided with anair intake pipe and a throttle valve therein, comprising a casingconnected to said pipe at a point therein on the engine side of saidthrottle valve, a control member in said casing displaceable in oppositedirections through a predetermined range of displacement and in one ofsaid directions under the influence of reduced pressure, transmittedfrom said intake pipe to said casing, a fuel injection pump having adelivery curve which rises relative to the consumption curve of theengine as the speed increases, means connected to said control memberand to said fuel pump operative to reduce the delivery of said pump inaccordance with the extent of displacement of said control member insaid one direction, resilient means operable to apply a resisting forceto said control member in opposition to the effect of said reducedpressure, additional resilient means operable to apply a resisting forceopposed to said first men tioned resilient means to said control member,said additional resilient means being ineflfective until said controlmember reaches a position of fuel delivery control for full load runningof the engine at speeds below maximum and both resilient meanscooperating to apply a resultant resisting force to said control memberin opposition to the efiect of said reduced pressure which is weaker inthe position of said control member for adjustment of the fuel deliveryof said pump within the full load range of said engine at speeds belowmaximum and with wide open Cir throttle than at speeds higher thanmaximum,

the resultant force exerted on said control member by said resilientmeans being so weak that said control member is sensitive to and movableby the small fluid pressure diiferences to which said control member issubjected when the engine runs with Wide open throttle under full loadat speeds lower than maximum speed.

8. A fuel supply system for internal combustion engines provided with anair intake pipe and a throttle valve therein, comprising a casingconnected to said pipe at a point therein on the engine side of saidthrottle valve, a control member in said casing and displaceable inopposite directions through a predetermined range of displacement and inone of said directions under the influence of reduced pressure,transmitted from said intake pipe to said casing, a fuel injection pumphaving a delivery curve which rises relative to the consumption curve ofthe engine as the speed increases, means connected to said controlmember and to said fuel pump operative to reduce the delivery of SearchRoom said pump in accordance with the extent of displacement of saidcontrol member in said one direction, resilient means operable to applya resisting force to said control member in opposition to the effect ofsaid reduced pressure, said resilient means comprising a relatively weakspring and an opposing relatively strong spring, said Weak springoperating alone during a portion of the stroke of said control memberand both springs cooperating to apply a resultant resisting force tosaid control member in opposition to the effect of said reduced pressurewhen the control member reaches a position for adjustment of fuel supplywithin the full load range of said engine at speeds below maximum, saidresultant force being weaker than the force exerted by said weak springalone and being so weak that said control member is sensitive to andmovable by the small fluid pressure differences to which said controlmember is subjected when the engine runs with wide open throttle underfull load at speeds lower than maximum speed.

9. A fuel supply system for internal combustion engines provided with anair intake pipe and a throttle valve therein, comprising a. casingconnected to said pipe at a point therein on the engine side of saidthrottle valve, a control member in said casing and displaceable inopposite directions through a predetermined range of displacement and inone of said directions under the influence of reduced pressure,transmitted from said intake pipe to said casing, a fuel injection pumphaving a delivery curve which rises relative to the consumption curve ofthe engine as the speed increases, means connected to said controlmember and to said fuel pump operative to reduce the delivery of saidpump in accordance with the extent of displacement of said controlmember in said one directionsa relatively strong spring of substantiallyno pretension and a pretensioned but relatively weak spring arranged inseries to apply a reslsting force to said control member in oppositionto the effect of said reduced pressure, and stop means between saidsprings to limit the exten sion of said weak spring and hold it underthe desired pretension whereby essentially only the force exerted bysaid relatively strong spring is exerted on said control member whensaid control member reaches a position for adjustment of fuel supplywithin the full load range of said engine at speeds below maximum, theforce exerted on said control member in opposition to the effect of saidreduced pressure in the full load range of said engine being so weakthat WILLY VOI'I. J OHANNES WEBER.

